Patent Document 1 describes the following means which is intended to employ a rejection determination device which has taken into consideration of an agreed service level. This rejection determination device employs a traffic control device installed between a particular server and a plurality of clients which monitors communication data exchange between the server and the clients, as a technical strategy for allowing the server to more stably provide services without degrading the service level. The rejection determination device estimates a waiting time associated with an exchange of communication data, and when the waiting time is predicted to be equal to or longer than a certain time, transmits an access regulation message to a client to reject an access.
In the foregoing traffic control device and a service system which employs the same, the rejection determination device, which has taken into consideration an agreed service level, suffers from the following problems because the rejection determination device is intended for simple exchanges of communication data and makes the determination of rejection only taking into consideration of an average response time related to the aforementioned data exchanges.
First, since the foregoing rejection determination device is intended for simple exchanges of communication data between a particular server and clients, the rejection determination device is incapable of identifying a combined workflow defined by a plurality of data exchanges unless appropriate means is provided, and cannot therefore be applied to the determination of rejection.
Second, in a long transaction in which a plurality of business application systems and a plurality of workflow systems are collaborated with one another, a compensation operation is performed when a rejection is exercised. When the compensation operation is performed, another transaction may be newly generated, and this transaction will affect the plurality of business application systems and the plurality of workflow systems, which are in collaboration, and also affects other combined workflows. However, the aforementioned rejection determination device does not assume the compensation operation, because it monitors only data exchanges between a server and clients, and cannot therefore apply the determination of rejection to a combined workflow.    Patent Document 1: JP2005-184165A